The present invention relates to a bookbinding apparatus for coating adhesive such as paste••on the spine of a sheet bundle, thereby performing a binding process, and pasting a cover sheet on the adhesive-coated spine.
A bookbinding apparatus for stacking sheets outputted from an image forming apparatus such as a copier or a printer to form a sheet bundle, performing the binding process for the sheet bundle, thereby binding a book is an apparatus used generally widely.
As a binding apparatus, there are a stapling device and a pasting device available, though when giving priority to good spreads, the pasting device is adopted.
Pasting must be executed surely so as to prevent sheets of the book-bound sheet bundle from coming out and to form the pasting surface in a uniform plane shape.
To respond to such a requirement, there is a proposal of a bookbinding apparatus for adjusting the amount of adhesive to be coated on the spine of a sheet bundle according to the thickness of the sheet bundle (for example, refer to Unexamined Japanese Patent Application Publication No. 2000-168265).
Bookbinding referred to as wrapping bookbinding for pasting one sheet (referred to as a cover sheet) composed of a cover sheet, a spine sheet, and a back cover sheet to the sheet bundle pasted in this way, then bending it in accordance with both edges of the spine of the sheet bundle, thereby binding a book is also executed.
In wrapping bookbinding finished satisfactorily, the square spine formed by bending a cover sheet along both edges of the spine of the sheet bundle is formed linearly and at right angles.
However, the square spine may not be formed linearly or in certain circumstances, a part of the adhesive coated on the spine may be non-uniformly forced out on the top page or last page of the sheet bundle.
Such a fault should be suppressed as far as possible from the viewpoint of bookbinding quality.